today I have received a report with picture concerning a colourringed BHG observed yesterday in Vienna.
I cannot identify this ring ( I had a look at the sites of Dirk Raes and Marco Basso) but maybe one of the experienced ringreaders here can help?

Thanks Ruud! Meanwhile I had the same idea. The observer did not take care of the gull species. I can understand that because Medgulls are extremely rare here in winter. I had only one some years ago, with Polish cr, also between BHG´s.
Today I received already ZRU8´s life history, an interesting one, the bird circles around between Germany, Poland, Czechia and Italy. No Le Portel (thanks god - saves a lot of time with working on the database ).
Wolfgang

It seems likely to me that this Black-headed Gull has been colour-ringed in the eastern part of Germany (the former East-Germany), as all species of gulls colour-ringed in this part of Germany have colour-rings that start with an 'X'.

You might contact:

(1): Hendrik Trapp h-trapp@web.de
Ringer of BHG using this kind of black colour-rings.

(2): arne-koehler@gmx.de and rones@t-online.de
Both involved in colour-ringing Common Gulls with such kind of white colour-rings. Maybe they also have ringed a few BHG's with such colour-rings.

I tend to advise you to send the same e-mail to all of these three ringers.

It seems likely to me that this Black-headed Gull has been colour-ringed in the eastern part of Germany (the former East-Germany), as all species of gulls colour-ringed in this part of Germany have colour-rings that start with an 'X'.

You might contact:

(1): Hendrik Trapp h-trapp@web.de
Ringer of BHG using this kind of black colour-rings.

(2): arne-koehler@gmx.de and rones@t-online.de
Both involved in colour-ringing Common Gulls with such kind of white colour-rings. Maybe they also have ringed a few BHG's with such colour-rings.

I tend to advise you to send the same e-mail to all of these three ringers.